JPS641876B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a hybrid magnetic bubble memory element in which a bubble transfer pattern formed by ion implantation and a bubble transfer pattern formed by a magnetic material pattern such as permalloy are mixed in one chip. In particular, the present invention relates to the configuration of alignment markers used during pattern fabrication in the device fabrication process.

Bubble memory, which is a non-volatile memory, does not require a moving mechanism and can be mounted on a printed circuit board, is highly reliable, has a long life, and has relatively fast information write/read access. It has better features than PID discs etc.

By the way, like other memory media, the storage capacity of magnetic bubble memory continues to increase from 1Mbit to 4Mbit, and patterns are becoming increasingly finer as a result, but it is difficult to form such fine patterns with high precision. To achieve this, accurate alignment technology between patterns during pattern formation is important.

[Conventional technology]

FIG. 5 shows a cross-sectional view of a conventional manufacturing process of a hybrid bubble device.

In the figure, 1' is a GGG (gatlinium gallium garnet) substrate in a wafer state, 2' is a magnetic thin film, 3' is a mask for forming an ion implantation transfer pattern (providing a large number of minor transfer paths for bubble storage), and 4 ' is a pattern for forming a positioning marker of the conductor pattern 8', 6a' is an ion implantation part, and 6
b' is an ion implantation transfer pattern, 6c' is a marker pattern for mask alignment of conductor pattern 8',
7', 10', 13' are insulating layers, 8' is a conductor pattern for bubble control, and 9' is a permalloy pattern 1.
1' is a marker pattern for positioning, 11' is a permalloy pattern forming a bubble transfer path such as a measure line, and 12' is a permalloy marker pattern.

First, as shown in (a), a magnetic thin film 2' of magnetic garnet or the like is formed on a GGG substrate 1' by a liquid phase growth method, and a transfer pattern forming mask 3' and a pattern 4' are simultaneously formed on its surface. At this time, a plurality of groups of masks 3' are formed on the wafer surface of the magnetic thin film 2' so that a plurality of chips are formed.
A predetermined number of patterns 4' are formed in areas not used as chips, that is, in the four corners of the wafer. 3',
The pattern material 4' is, for example, Cr-Au. From this state, ions such as Ne or hydrogen are implanted multiple times into the entire surface of the magnetic thin film 2' as required.

Next, as shown in (b), the mask 3' and the pattern 4' are removed by etching, and the ion implantation transfer pattern 6b' and the marker pattern 6c' are in the shape of a contiguous disk and form a minor transfer path surrounded by the ion implantation part 6a'. appears. At this time, the ion implanted portion 6a' is raised by about several tens of angstroms, and a slight step is formed. Thereafter, as shown in (c), an insulating layer 7' made of SiO ₂ or the like is coated, and a conductive pattern 8' and a marker pattern 9' are simultaneously formed on the insulating layer 7' using the marker pattern 6' as a positioning marker between the patterns. . At this time, the step portion in the ion-implanted part 6a' covered by the insulating layer 7' becomes smaller, and the position of the marker pattern 6c' becomes unclear (blurred), so the alignment accuracy between the transfer pattern 6b' and the conductor pattern 8' becomes smaller. is bad, and in the worst case it is ±0.3 μm. After that, as shown in (d), an insulating layer 1 made of PLOS (poly ladder organo siloxane) resin etc.
A flattening process of 0' is performed, and a permalloy pattern 11' and a permalloy marker pattern 12' are simultaneously patterned thereon using the marker pattern 9' and a positioning marker between the patterns, and a protective insulating layer 13 is formed. ' to produce a wafer-shaped bubble memory element. Thereafter, a large number of bubble memory devices are obtained by dividing the wafer.

By the way, the process of (d) is permalloy pattern 11'
This is an important step because the alignment accuracy of the transfer pattern 6b' greatly affects the characteristics of the bubble memory element, but the step position of the transfer pattern 6b' is extremely difficult to see due to the insulating layers 7', 10', etc.

For this reason, in the past, positioning was performed using the conductive marker pattern 9' and the permalloy marker pattern 12', and the positional relationship between the transfer pattern 6b' and the permalloy pattern 11' was indirectly adjusted. ' includes extremely large formation errors, making it impossible to align patterns with each other with high precision.

[Problem that the invention seeks to solve]

Conventionally, the alignment marker is also etched when etching the transfer pattern forming mask after ion implantation, making it very difficult to see the alignment marker portion of the ion implantation transfer pattern. Moreover, since the marker portion is coated with an insulating layer, the alignment with the mask for forming the conductive pattern becomes even more unclear, and it becomes almost invisible in the process of forming the permalloy pattern. For this reason, in the past, the alignment of the ion implantation transfer pattern and the permalloy pattern had to be done indirectly using a conductor marker pattern, making it impossible to form a highly accurate pattern and making it difficult to obtain a highly reliable, high-density bubble memory element. I couldn't do it.

An object of the present invention is to solve the above problems.

[Means for solving problems]

As a means for solving the above problems, in the present invention, at least two marker patterns for mask alignment between a conductor pattern for an ion implantation transfer pattern and a magnetic material pattern are formed on a magnetic thin film in a raised shape and arranged in parallel. A conductor pattern marker pattern is laminated on one mask alignment marker pattern via an insulating layer, and a magnetic material pattern marker pattern is laminated on the other mask alignment marker pattern via an insulating layer. To provide a magnetic bubble memory element characterized by:

[Effect]

With this means, since the marker patterns for positioning between patterns are formed in a raised shape on the magnetic thin film, the problem of the marker patterns being difficult to see is eliminated, and highly accurate positioning between patterns can be performed.

〔Example〕

The present invention will be explained using the production of a hybrid bubble memory device as an example.

1A to 1D are cross-sectional views showing the manufacturing process of a hybrid bubble memory device according to a first embodiment of the present invention, and FIGS. 2A to 2C are sectional views showing the manufacturing process of a hybrid bubble memory device according to another embodiment of the present invention. FIG. 3 is a cross-sectional view showing the structure of a transfer path of a hybrid bubble memory element manufactured according to the present invention, and FIG. 4a,
b is a diagram showing the junction of the minor transfer path and major transfer path in Figure 3, a is a plan view, and b is a-a in figure a.
FIG.

In these figures, 1 is GGG (gatlinium)
gallium garnet) substrate, 2 is a magnetic thin film,
3 and 14 are masks for forming an ion implantation transfer pattern, 4 is a marker pattern for a conductor pattern, 5 is a marker pattern for a permalloy pattern, 6, 1
8 is an ion implantation part, 7, 10, 13 is an insulating layer, 8
is a conductor pattern, 9 is a marker pattern of a conductor pattern, 11 is a permalloy pattern, 12 is a marker pattern of a permalloy pattern, 15 and 16
15' is a mask for forming a marker pattern for alignment between patterns; 15' is a marker pattern for a permalloy pattern; 16' is a marker pattern for a conductor pattern; 17 is a resist; 19 is an ion implantation transfer pattern; 20 is a marker section; 20' 21 is a bubble generator, 22 is a write major line, 22' is a read major line, 23 is a write gate that performs a transfer function and a swap function, 24 is a minor loop, and 25 is a block replicate function. readout gate, 26 is a detector, 27, 28,
29 is a permalloy pattern.

First, the overall structure of the magnetic bubble memory element according to the present invention will be explained with reference to FIGS. 3 and 4.

This magnetic bubble memory element is constructed by patterning and laminating a bubble generator 21, major lines 22, 22', a write gate 23, a minor loop 24, a read gate 25, and a detector 26 on a magnetic thin film 2. In this magnetic bubble memory device, bubble information generated by the bubble generator 21 is transferred through the major line 22 and written into the minor loop 24 by the write gate 23. The information in the minor loop 24 is read out to the major line 22' by the read gate 25,
It is detected by the detector 26.

The junction of the major line and the minor loop in FIG. 3 is as shown in FIGS.
4 is formed, an insulating layer 7 is coated thereon to form a U-shaped conductor pattern 8, and an insulating layer 10 is further coated thereon to form measure lines 22, 2.
Permalloy patterns 27, 28, which constitute 2'
29 is formed, the pickled permalloy pattern 27 faces the cusp of the minor loop 24, and the conductor pattern 8 is arranged on a line connecting both.

At the junction, the transfer of bubbles from the minor loop 24 to the major lines 22, 22' or from the major lines 22, 22' to the minor loop 24 is controlled by the current pulse applied to the conductor pattern 8; It is necessary to accurately form the positional relationship between the minor loop 24 and the permalloy pattern 27.

Next, embodiments of the characteristic portions of the present invention will be described with reference to FIGS. 1 and 2.

FIGS. 1A to 1D are cross-sectional views showing the manufacturing process of a hybrid bubble memory device according to a first embodiment of the present invention, in which the positional relationship of patterns can be formed with high precision.

First, as shown in a, when forming the mask 3 for forming the transfer pattern of Au or Cr-Au on the magnetic thin film 2, the alignment marker pattern 4 for the conductor pattern and the alignment marker pattern 5 for the permalloy pattern are simultaneously formed, and ions are implanted. I do. After that, the mask 3 for forming the transfer pattern is etched.
By applying a resist, marker patterns 4 and 5 are left as they are without being etched, and are formed into a raised shape.

In this state b, marker patterns 4 and 5 are formed at the four corners of the wafer where they do not affect the device characteristics. Further, as shown in c, an insulating layer 7 is coated, and a conductive pattern 8 and a marker pattern 9 are formed using the marker pattern 4 as a pattern positioning (reference). For positioning at this time, since the marker patterns 4 and 5 are present, even if the insulating layer 7 is covered, the protrusions are clear and positioning becomes easy.

Then, as shown in d, planarization is performed using a resin insulating layer 10, and a permalloy pattern 11 and a marker pattern 12 are formed thereon using the marker pattern 5 as pattern positioning. Finally, by forming the insulating layer 13, the bubble memory element according to the present invention is manufactured.

FIG. 2 is a diagram showing an embodiment of the present invention.

In the second embodiment, first, as shown in FIG. 2a, a transfer pattern forming mask 14 and alignment marker pattern forming masks 15 and 16 are formed,
Thereafter, ions are implanted into the entire surface to form an ion implantation section 18. Next, as shown in b, a resist 17 is applied to the transfer pattern forming mask 14 and its periphery (memory use area), excluding the marker portion 20. Next, the ion-implanted part 18 is etched into the marker part 2 by taking advantage of the fact that the etching speed is faster than that of non-ion implanted part 18.
A groove 20' is formed by etching the 0 ion implanted portion 18 to remove a portion of the bubble crystal. Thereafter, as shown in c, by removing the resist 17, the transfer pattern forming mask 14, and the masks 15 and 16, the ion implantation transfer pattern 19 is formed, and at the same time, the raised conductor pattern and permalloy pattern mask alignment markers are formed. Patterns 15' and 16' are formed.

The state of FIG. 2c according to this embodiment is equivalent to that of FIG. 1b, and thereafter conductor and permalloy patterns are formed in the same manner as in FIGS. 1c and d.

This embodiment is particularly effective when there is a risk that the marker masks 14 and 15 may be peeled off during the cleaning step before forming the insulating layer as shown in FIG. 1c.

〔Effect of the invention〕

According to the magnetic bubble memory device of the present invention, since the marker pattern for alignment between patterns is formed in a raised shape on the magnetic thin film, the marker pattern is not difficult to see, so the accuracy of alignment between patterns is improved. , high-density bubble memory devices with good device characteristics can be manufactured with good reproducibility,
Its practical effects are enormous.

[Brief explanation of the drawing]

1A to 1D are cross-sectional views for explaining a first embodiment of the method for manufacturing a magnetic bubble memory device according to the present invention, and FIG. 2 is a cross-sectional view for explaining another embodiment of the method for manufacturing a magnetic bubble memory device according to the present invention. FIG. FIG. 3 is a block diagram of a bubble transfer path of a hybrid bubble memory element manufactured according to the present invention, and FIGS. 4a and 4b are an enlarged plan view and cross-sectional view of the junction between the minor loop and permalloy pattern in FIG. 3. be. FIGS. 5a to 5d are diagrams for explaining a method of manufacturing a conventional magnetic bubble memory element. [Explanation of symbols], 3, 14...mask for forming ion implantation transfer pattern, 4, 16'... marker pattern for alignment between patterns for conductor pattern, 5, 15'... for permalloy pattern Marker pattern for alignment between patterns, 6, 18... ion implantation part, 8... conductor pattern, 9... marker pattern of conductor pattern,
11... Permalloy pattern, 12... Permalloy pattern marker pattern.

Claims (1)

[Claims] 1. A hybrid magnetic bubble memory element in which an ion implantation transfer pattern is formed in a magnetic thin film by ion implantation, and a conductive pattern and a magnetic material pattern are formed on the magnetic thin film by covering an insulating layer. At least two marker patterns for mask alignment between the conductor pattern and the magnetic material pattern with respect to the ion implantation transfer pattern are formed on the magnetic thin film in a raised shape and juxtaposed, one of which is used for mask alignment. A marker pattern of the conductive pattern is laminated on the marker pattern with the insulating layer interposed therebetween, and a marker pattern of the magnetic material pattern is laminated on the other marker pattern for mask alignment with the insulating layer interposed therebetween. A magnetic bubble memory element characterized by: 2. The magnetic material according to claim 1, wherein the raised marker pattern for mask alignment is formed of the mask material at the same time as the mask for forming the ion implantation transfer pattern is formed. bubble memory element. 3. The raised marker pattern for mask alignment is generated by etching away the ion-implanted portion of the marker portion of the magnetic thin film to form a groove. magnetic bubble memory element.